The present invention relates to telecommunication systems, and in particular, to radio transceiver systems and techniques.
Transceivers are used in wireless communications to transmit and receive electromagnetic waves in free space. In general, a transceiver comprises three main components: a transmitter, a receiver, and an LO generator or frequency synthesizer. The function of the transmitter is to modulate, upconvert, and amplify signals for transmission into free space. The function of the receiver is to detect signals in the presence of noise and interference, and provide amplification, downconversion and demodulation of the detected the signal such that it can be displayed or used in a data processor. The LO generator provides a reference signal to both the transmitter for upconversion and the receiver for downconversion.
Transceivers have a wide variety of applications ranging from low data rate wireless applications (such as mouse and keyboard) to medium data rate Bluetooth and high data rate wireless LAN 802.11 standards. However, due to the high cost, size and power consumption of currently available transceivers, numerous applications are not being fully commercialized. A simplified architecture would make a transceiver more economically viable for wider applications and integration with other systems. The integration of the transceiver into a single integrated circuit (IC) would be an attractive approach. However, heretofore, the integration of the transceiver into a single IC has been difficult due to process variations and mismatches. Accordingly, there is a need for an innovative transceiver architecture that could be implemented on a single IC, or alternatively, with a minimum number of discrete off-chip components that compensate for process variations and mismatches.
In one aspect of the present invention, an oscillator circuit includes an oscillator to generate a first signal having a first frequency, a second oscillation source to generate a second signal having a second frequency, and a mixer to mix to the first and second signals.
In another aspect of the present invention, an oscillator circuit, comprising oscillation means for generating a first signal having a first frequency, signal generation means for generating a second signal having a second frequency, and mixer means for mixing the first and second signals.
In yet another aspect of the present invention, a transceiver includes a local oscillator generator having an oscillator with a first signal having a first frequency, a frequency divider coupled to the oscillator to divide the first frequency off the first signal to produce a second signal having a second frequency, the frequency divider having a programmable divisor, and a mixer to mix the first and second signals, and a controller to program the divisor.
In still another aspect of the present invention, a method of generating a signal having a signal frequency includes generating a first signal having a first frequency, dividing the first frequency to generate a second signal having a second frequency, and mixing the first and second signals to generate the signal frequency.
In a further aspect of the present invention, a method of generating a local oscillator having a signal frequency includes generating a first signal having a first frequency, generating a second signal having a second frequency, and mixing the first and second signals to generate the signal frequency.
It is understood that other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein it is shown and described only embodiments of the invention by way of illustration of the best modes contemplated for carrying out the invention. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.